METHODS OF DETECTING SERIES ARCS IN ELECTRICAL SIGNALS

• US 20090171603A1
• Filed: 12/28/2007
• Published: 07/02/2009
• Est. Priority Date: 12/28/2007
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Vijayan, Pradeep, Prasad, Vljaysai, Rivers, Cecil JR., Changali, Sriram
• Application Number:
  US11/965,885
• Publication Number:
  US 20090171603A1
• Time in Patent Office: Days
• US Class Current: 702/66
• CPC Class Codes: G01R 31/1227 of components, parts or materials G01R31/1209, G01R31/1218, G01R31/18 take precedence; circuits therefor G01R31/14; testing vessels of electrodes G01R31/16
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 1/0092 concerning the data processing means, e.g. expert systems, neural networks

Abstract

A method of detecting a series arc fault in an alternating current electrical signal is provided. A method for detecting a series arc fault in an alternating current electrical signal, comprising: a) calculating discrete wavelet coefficients using a current signal as an input for the discrete wavelet coefficient calculations, and outputting discrete wavelet coefficient filtered output; b) subsampling the discrete wavelet coefficient filtered output and outputting a subsampled output; c) calculating critical variables from the subsampled output; d) determining from the critical variables whether a series arc fault is present in the current signal; and e) outputting an signal indicating that a series arc fault is present in the current signal, if substantially all of the critical variables meet a predetermined criteria.

Claims

1. A method for detecting a series arc fault in an alternating current electrical signal, comprising:

a) calculating discrete wavelet coefficients using a current signal as an input for the discrete wavelet coefficient calculations, and outputting discrete wavelet coefficient filtered output;

b) subsampling the discrete wavelet coefficient filtered output and outputting a subsampled output;

c) calculating critical variables from the subsampled output;

d) determining from the critical variables whether a series arc fault is present in the current signal; and

e) outputting a signal indicating that a series arc fault is present in the current signal, if substantially all of the critical variables meet a predetermined criteria.

2. The method of claim 1 further comprising:

f) outputting a signal indicating that the series arc fault is not present in the current signal, if one or more of the critical variables do not meet the predetermined criteria.

3. The method of claim 2 further comprising repeating a) through e).

4. :

The method of claim 1 further comprising, before a), passing the current signal through a filter to provide a filtered current signal.

5. :

The method of claim 1 wherein the discrete wavelet coefficient calculations comprises sub-sampling and filtering calculations.

6. :

the method of claim 1 wherein the discrete wavelet coefficient filtered output comprises decomposition and reconstruction discrete wavelet filtered output.

7. :

The method of claim 1 wherein the subsampled output comprises a subsampled signal with changed time and frequency resolutions as compared to the discrete wavelet coefficient filtered output used in the subsampling calculation.

8. :

The method of claim 1 wherein critical variables from the subsampled output comprises;

a first critical variable substantially equal to the range of detail coefficient divided by a norm of the fundamental component;

a second critical variables substantially equal to the range of detail coefficient divided by an RMS value of the fundamental component; and

a third critical variables substantially equal to the range of detail coefficient divide by a maximum value of the fundamental component; and

a fourth critical variable substantially equal to a range of detail coefficient divided by a fundamental component of the input signal.

9. :

A method of detecting a series arc fault in an alternating current electrical signal, the method comprising;

a) obtaining a sampled of the alternating current electrical signal for mathematical analysis;

b) filtering the sampled alternating current electrical signal to remove electrical noise;

c) calculating discrete wavelet coefficients using wavelet decomposition;

d) reconstructing the alternating current electrical signal and fundamental component associated with a predetermined discrete wavelet coefficient;

e) calculating a critical ratio; and

f) detecting a series arc fault in the alternating current electrical signal by using the critical ratio as a threshold to compare to the alternating current electrical signal.

10. :

A computer program product comprising;

a program storage device readable by a circuit interrupter, tangibly embodying a program of instructions executable by the circuit interrupter to perform a method of detecting a series arc fault in an alternating current electrical signal, the method comprising;

a) calculating discrete wavelet coefficients using a current signal as an input for the discrete wavelet coefficient calculations, and outputting discrete wavelet coefficient filtered output;

b) subsampling the discrete wavelet coefficient filtered output and outputting a subsampled output;

c) calculating critical variables from the subsampled output;

d) determining from the critical variables whether a series arc fault is present in the current signal; and

e) outputting a signal indicating that a series arc fault is present in the current signal, if substantially all of the critical variables meet a predetermined criteria.